Which statement describes Class 2M lasers?

Which statement describes Class 2M lasers?

• A. They are safe without collecting optics
• B. They are intermediate-power visible lasers potentially hazardous if viewed with collecting optics in under 0.25 seconds
• C. They are only hazardous when used in Class 4
• D. They are invisible lasers

Answer: (B)

Class 2M lasers are low-power visible devices that are generally safe to view directly for a very short time because the eye’s natural blink reflex can protect against brief exposure. The key concern with Class 2M is what happens when you use collecting optics—things like magnifiers, microscopes, or telescopes. These optics concentrate the beam, dramatically increasing the light’s intensity on the retina. If that concentrated beam is viewed for even a fraction of a second, it can cause retinal damage. That’s why the statement describing them as intermediate-power visible lasers potentially hazardous if viewed with collecting optics in under 0.25 seconds is the best fit: it acknowledges both the visible nature and the specific, optics-enabled hazard. Other options don’t fit: they aren’t safe to view without any caution (the optics-collecting hazard matters), they are not invisible (they’re visible), and their hazard isn’t limited to Class 4—2M can be hazardous when viewed through collecting optics despite being a lower class.

Class 2M lasers are low-power visible devices that are generally safe to view directly for a very short time because the eye’s natural blink reflex can protect against brief exposure. The key concern with Class 2M is what happens when you use collecting optics—things like magnifiers, microscopes, or telescopes. These optics concentrate the beam, dramatically increasing the light’s intensity on the retina. If that concentrated beam is viewed for even a fraction of a second, it can cause retinal damage. That’s why the statement describing them as intermediate-power visible lasers potentially hazardous if viewed with collecting optics in under 0.25 seconds is the best fit: it acknowledges both the visible nature and the specific, optics-enabled hazard.

Other options don’t fit: they aren’t safe to view without any caution (the optics-collecting hazard matters), they are not invisible (they’re visible), and their hazard isn’t limited to Class 4—2M can be hazardous when viewed through collecting optics despite being a lower class.